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diff --git a/libodb-pgsql/odb/pgsql/connection-factory.hxx b/libodb-pgsql/odb/pgsql/connection-factory.hxx
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+++ b/libodb-pgsql/odb/pgsql/connection-factory.hxx
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+// file      : odb/pgsql/connection-factory.hxx
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_PGSQL_CONNECTION_FACTORY_HXX
+#define ODB_PGSQL_CONNECTION_FACTORY_HXX
+
+#include <odb/pre.hxx>
+
+#include <vector>
+#include <cstddef> // std::size_t
+#include <cassert>
+
+#include <odb/details/mutex.hxx>
+#include <odb/details/condition.hxx>
+#include <odb/details/shared-ptr.hxx>
+
+#include <odb/pgsql/version.hxx>
+#include <odb/pgsql/forward.hxx>
+#include <odb/pgsql/connection.hxx>
+
+#include <odb/pgsql/details/export.hxx>
+
+namespace odb
+{
+  namespace pgsql
+  {
+    class LIBODB_PGSQL_EXPORT new_connection_factory: public connection_factory
+    {
+    public:
+      new_connection_factory () {}
+
+      virtual connection_ptr
+      connect ();
+
+    private:
+      new_connection_factory (const new_connection_factory&);
+      new_connection_factory& operator= (const new_connection_factory&);
+    };
+
+    class LIBODB_PGSQL_EXPORT connection_pool_factory:
+      public connection_factory
+    {
+    public:
+      // The max_connections argument specifies the maximum number of
+      // concurrent connections this pool will maintain. If this value
+      // is 0 then the pool will create a new connection every time all
+      // of the existing connections are in use.
+      //
+      // The min_connections argument specifies the minimum number of
+      // connections that should be maintained by the pool. If the
+      // number of connections maintained by the pool exceeds this
+      // number and there are no active waiters for a new connection,
+      // then the pool will release the excess connections. If this
+      // value is 0 then the pool will maintain all the connections
+      // that were ever created.
+      //
+      connection_pool_factory (std::size_t max_connections = 0,
+                               std::size_t min_connections = 0)
+          : max_ (max_connections),
+            min_ (min_connections),
+            in_use_ (0),
+            waiters_ (0),
+            cond_ (mutex_)
+      {
+        // max_connections == 0 means unlimited.
+        //
+        assert (max_connections == 0 || max_connections >= min_connections);
+      }
+
+      virtual connection_ptr
+      connect ();
+
+      virtual void
+      database (database_type&);
+
+      virtual
+      ~connection_pool_factory ();
+
+    private:
+      connection_pool_factory (const connection_pool_factory&);
+      connection_pool_factory& operator= (const connection_pool_factory&);
+
+    protected:
+      class LIBODB_PGSQL_EXPORT pooled_connection: public connection
+      {
+      public:
+        pooled_connection (connection_pool_factory&);
+        pooled_connection (connection_pool_factory&, PGconn*);
+
+      private:
+        static bool
+        zero_counter (void*);
+
+      private:
+        friend class connection_pool_factory;
+
+        shared_base::refcount_callback cb_;
+      };
+
+      friend class pooled_connection;
+
+      typedef details::shared_ptr<pooled_connection> pooled_connection_ptr;
+      typedef std::vector<pooled_connection_ptr> connections;
+
+      // This function is called whenever the pool needs to create a new
+      // connection.
+      //
+      virtual pooled_connection_ptr
+      create ();
+
+    protected:
+      // Return true if the connection should be deleted, false otherwise.
+      //
+      bool
+      release (pooled_connection*);
+
+    protected:
+      const std::size_t max_;
+      const std::size_t min_;
+
+      std::size_t in_use_;  // Number of connections currently in use.
+      std::size_t waiters_; // Number of threads waiting for a connection.
+
+      connections connections_;
+
+      details::mutex mutex_;
+      details::condition cond_;
+    };
+  }
+}
+
+#include <odb/post.hxx>
+
+#endif // ODB_PGSQL_CONNECTION_FACTORY_HXX